HISTORY AND METODOLOGY OF VACUUM PHYSICS
PART III. VACUUM PHYSICS FROM DISCOVERY OF
ATMOSPHERIC PRESSURE UNTIL PRESENT DAY
In the third part of the paper it is described the history and methodology
of physics since the discovery of atmospheric pressure vacuum. The decisive
contributions of vacuum physics to collapse system concepts inherited from the
ancient Greeks and canonized by the medieval Christians and Muslims
theologians is shown. At the same time, the paper describes first physical,
chemical and biological experiments performed in vacuum space and shows
the difficulties in explaining the nature of emptiness.
Particular attention is given to the concept of ether in the history of
science and philosophy and concept of vacuum in the science and modern
technique. It is shown the distinct difference between the notion of technical
vacuum (classical) and the physical vacuum. Finally, the evolution of the
concept of vacuum in the materialist philosophy, science and technology is
summarized.
Keywords: atom, molecule, void, vacuum, ether, technical vacuum,
physical vacuum, the mean free path length, Knudsen number, flow
Cuvinte cheie: atom, moleculă, spaţiu gol, vid, eter, vid tehnic, vid fizic,
lungimea drumului liber mediu, număr Knudsen, curgere

HISTORY AND METODOLOGY OF VACUUM PHYSICS
PART II. THE DISCOVERY OF ATMOSPHERIC PRESSURE
AND THE COLLAPSE OF THE „ABHORS VACUUM” MYTH
Based on extensive documentation and a rigorous selection of the
bibliography, the paper presents the main facts and historical moments that led
to the discovery of atmospheric pressure and vacuum in 1643. The first
experiment showed that actual vacuum production was monitored and carried
out in 1641 by Gasparo Berti, who designed and tested the first water
barometer. The discovery of atmospheric pressure and vacuum favored the
invention of the mercury barometer in 1644, the air pump in 1654 and
gunpowder engine in 1678. The paper shows the contributions of Galileo
Galilei, Evangelista Torricelli, Blaise Pascal and Otto von Guericke to dispel the
myth ,,horror vacuum” and founding scientific bases of vacuum physics.
Keywords: abhors vacuum, vacuum force error, space vacuum,
atmospheric pressure, barometer, air pump, water pump, gunpowder engine
Cuvinte cheie: oroare de vid, forţa de oroare a vidului, spaţiu vid,
presiune atmosferică, barometru, pompă de aer, pompă de apă, motor cu praf
de puşcă

HISTORY AND METODOLOGY OF VACUUM PHYSICS
PART I. HISTORICAL CONCEPT OF VACUUM WITHIN
ANCIENT AND MEDIEVAL SCIENCE AND PHILOSOPHY
The paper presents the main aspects and concept of the evolution of
vacuum in the ancient and medieval history of science and philosophy. It is
obvious that even in ancient times vacuum was at the center of philosophical
controversy of two antagonistic conceptions. Naturalist philosophers believed
that the universe consists of atoms and absolutely empty space without of
matter. In contrast to the materialistic school Ionian philosophers have
proposed the idea on the continuity of matter and the impossibility of existence
of voids, Aristotle’s idea was further developed by postulate ,,nature abhors a
vacuum”.
False teaching about Aristotle’s concept of vacuum dominated science
and philosophy until the middle of the XVII th century, taking in the era of the
,,darkness” of the Middle Ages even a mystical religious forms. Particular
attention is given to the concept of vacuum in science and philosophy of Arab
Muslim and application of physical properties of thin air for operating technical
means in the Greek period.
Keywords: universe, nature, matter, motion, atom, void, vacuum, pump,
air, water, nature abhors vacuum
Cuvinte cheie: univers, natură, materie, mişcare, atom, spaţiu gol, vid,
pompă, aer, apă, natura are oroare de vid

THE DIMENSIONING OF THE AXIAL TURBINES
In this paper is presented a new method for calculating the axial
hydraulic turbines, whose applicability is demonstrated by a numerical
example. This method is based on the torque developed by the turbine
rotor, which from reasons of simplicity, has been obtained by the 
theorem of dimensional analysis. Calculation results with the proposed
method for the flow of small water falls are in a good accordance with
those in the specialty literature. The method should be extended and
verified for large and medium flow and water falling.
Keywords: turbine, rotor, method, calculation, water, hydraulic,
axial
Cuvinte cheie: turbină, rotor, metodă, calcul, apă, hidraulic, axial

HISTORICAL AND CRITICAL REVIEW OF THE ANEMOMETRY
In this paper, on the base of extensive documentary, are present the main events and facts, which have had led to the evolution in time of both anemometry and the thermo-anemometry. At the same time, it shows the priority development of anemometers and thermo-anemometers. This study will be helpful to the specialists skilled in this area.
Keywords: anemometer, therm-anemometer, kata-thermometer, speed, wind, air, palette, cup
Cuvinte cheie: anemometru, termoanemometru, catatermometru, viteză, vânt, aer, paletă, cupă

HISTORICO-CRITICAL REVIEW OF DIMENSIONAL ANALYSIS
On the base of numerous literatures a critical review of main facts and
events that played a significant role in the history of dimensional analysis will be
presented. Dimensional analysis appeared in the antiques with the necessity to
qualitatively describe and understand the physical world and was fructuously
developed in the works of Galileo Galilei, Pierre-Marie-François Daviet de
Foncenex, Jean Baptiste Joseph Fourier and John William Strutt. Application of
dimensional analysis on a large scale began after 1914, when Edgar
Buckingham demonstrated his Π− theorem and Percy W. Bridgman published
his „Dimensional analysis” in 1922.
Keywords: history, geometrical dimensions, physical dimensions,
principle of dimensional homogeneity, Π – theorem, dimensional analysis
Cuvinte cheie: istorie, dimensiuni geometrice, dimensiuni fizice, principiul
de omogenitate dimensională, teorema Π , analiză dimensionalăDescarcare text

CONTRIBUTIONS TO THE
ALGEBRAIC THEORY OF DIMENSIONAL ANALYSIS
Dimensional analysis is based on the tacitly accepted idea, that physical
quantities, units and their dimensions represents algebraically factors, with
which you can perform ordinary operations like with the numbers. To
demonstrate the viability of this idea in the present paper were formulated and
proved four theorems of algebraic theory of dimensional analysis, taking as
starting point the relation between the definition of the physical quantities and
the invariance principle of the physical laws. It also shows, whether two
quantities are mechanical in nature, the product or multiplier of them is also of
mechanical nature. This correlations can be extended to others physical
quantities such as heat, electricity, electromagnetic, chemical etc.
Keywords: physical quantity, unit, numerical value, dimension,
dimensional analysis
Cuvinte cheie: mărime fizică, unitate, valoare numerică, dimensiune,
analiză dimensionalăDescarcare text